The short answer is: no. Wavelength does not matter. Not for native
data anyway.
I wrote a paper about this recently. It is open access:
http://dx.doi.org/10.1107/S0907444910007262
In particular, check out Figure 2. The two solid lines are pretty darn
flat, and that means the wavelength
the absorbed energy itself follows the square of the wavelength.
Regards
Colin
-Original Message-
From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Bart Hazes
Sent: 16 February 2012 15:01
To: ccp4bb
Subject: Re: [ccp4bb] choice of wavelength
Hi Andrew,
I completely a
Hi Andrew,
I completely agree and it is what I meant by "(assuming the full photon
energy is captured)". If the fraction of photons counted goes up at
longer wavelengths than the relative benefit of using longer wavelength
is even more pronounced on Pilatus. So for native data sets the
wavele
On 15 Feb 2012, at 23:55, Bart Hazes wrote:
Diffracted intensity goes up by the cube of the wavelength, but so
does absorption and I don't know exactly about radiation damage. One
interesting point is that on image plate and CCD detectors the
signal is also proportional to photon energy, s
Dear Colleagues,
I think the following paper will be of particular interest for some
aspects of this thread:-
J. Appl. Cryst. (1984). 17, 118-119[ doi:10.1107/S0021889884011092 ]
Optimum X-ray wavelength for protein crystallography
U. W. Arndt
Abstract: If the diffraction pattern from crystall
Diffracted intensity goes up by the cube of the wavelength, but so does
absorption and I don't know exactly about radiation damage. One
interesting point is that on image plate and CCD detectors the signal is
also proportional to photon energy, so doubling the wavelength gives 8
times diffract
Acta Cryst. (1997). D53, 734-737[ doi:10.1107/S0907444997007233 ]
The Ultimate Wavelength for Protein Crystallography?
I. Polikarpov, A. Teplyakov and G. Oliva
http://scripts.iucr.org/cgi-bin/paper?gr0657
may give some insights.
To the OP, have you solved the structure? In some cases, s
Well, but there is more scattering with lower energy as well. The
salient parameter should probably be scattering per damage. I remember
reading some systematic studies a while back in which wavelength
choice ended up being insignificant, but perhaps there is more info
now, or perhaps I am remember
No impact ? Longer wavelength more absorption more damage. But between the
choices given no problem.
Spread of spots might be better with 1.0 versus 0.9 but that depends on your
cell and also how big your detector is. Given your current resolution none of
the mentioned issues are deal breakers.
I would say the better practice would be to collect higher
multiplicity/completeness, which should have a great impact on maps.
Just watch out for radiation damage though. I think the wavelength
will have no impact whatsoever.
JPK
On Wed, Feb 15, 2012 at 4:23 PM, Seungil Han wrote:
> All,
> I am
All,
I am curious to hear what our CCP4 community thoughts are
I have a marginally diffracting protein crystal (3-3.5 Angstrom resolution)
and would like to squeeze in a few tenth of angstrom.
Given that I am working on crystal quality improvement, would different
wavelengths make any differenc
: CCP4BB@JISCMAIL.AC.UK
Subject: [ccp4bb] Choice of wavelength
Hi all.
When collecting data, is there a specific wavelength to be chosen at
synchrotron source? Does it make difference between 0.9 and 1.5 A, for example?
I know it is important for SAD/MAD but how about MIR?
Thank you.
Theresa
On Mon, 2012-02-13 at 21:02 +, Theresa H. Hsu wrote:
> Hi all.
>
> When collecting data, is there a specific wavelength to be chosen at
> synchrotron source? Does it make difference between 0.9 and 1.5 A, for
> example? I know it is important for SAD/MAD but how about MIR?
>
> Thank you.
>
If you are not looking for a specific metal, you can play it safe and
collect a redundant native data set at 0.9 A and one at 1.5 A, to check
for Ca,Cl,SO4 etc and other anomalous scatterers
cheers
Preben
On 2/13/12 10:02 PM, Theresa H. Hsu wrote:
Hi all.
When collecting data, is there a speci
Hi all.
When collecting data, is there a specific wavelength to be chosen at
synchrotron source? Does it make difference between 0.9 and 1.5 A, for example?
I know it is important for SAD/MAD but how about MIR?
Thank you.
Theresa
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